Hair loss drug finasteride can cause debilitating side-effects, men say

WARNING: This story contains discussion of suicide. 

Marc Turner's mother remembers him coming home with a prescription in the fall of 2020.

"He was really excited to take it. I can literally remember him running in the house," said Denise Turner. "He was like: 'I know it's a lifelong drug, but it's going to work.'"

The 35-year-old living in Mississauga, Ont., had been concerned about losing his hair. The medication, a popular drug called finasteride, promised to curb the issue. His doctor warned him side-effects — erectile dysfunction and a lowered libido — were possible, but the doctor told Marc these symptoms would cease if he stopped the medication. 

Marc's excitement was short-lived. 

"Three weeks after starting, he said to me: 'I'm having some funny feelings in my head, like brain fog or something,'" his mother said. 

When Marc lowered his dose, the side-effects got worse. After a few months, he quit completely. 

Denise Turner said that's when the family's nightmare truly began. Over the next few months, her once-healthy son's condition worsened. The loss of his sexual functions continued and he experienced fatigue, anxiety, tinnitus and a plethora of physical symptoms. 

Finasteride — or Propecia, its most popular brand name — was invented by Merck. The pharmaceutical company insists that it's rare for men on the medication to experience side-effects, and has long maintained they vanish once the medication is stopped. 

But 25 people interviewed by CBC/Radio Canada during a six-month investigation of finasteride's side-effects tell a different story. They say the drug caused sexual, psychological and physical side-effects for them that have lasted months if not years after they ceased taking the drug. 

Denise Turner said the worst of her son's symptoms was anhedonia, the inability to feel emotions.

"I used to fight with him. I'd say: 'What do you mean you don't feel love, Marc?' He'd say, 'I can't feel it anymore, mom. There's no comfort anywhere.'"

She said the medical community was at a loss.

"His doctor was saying: 'There's no way Marc, this drug would not do that, you're off the drug. There should be no problems.'"